That would definitely be scary hun! If your doc doesn't call you back soon go to emerg. Or a walk in clinic.
Try not to worry, spotting early on in pregnancy is normal , but if you can fill a pad, have cramping then you should take care of it immediately.
I can't really explain it to you, i'm not a doctor but my advice is see a doctor asap, not only to make sure your okay, but to ease your mind..And relax as much as you can, stressing and freaking out won't help ya !
Good luck and let us know how it goes